<!DOCTYPE html>
<html lang="zh">
<head>
    <meta charset="UTF-8">
    <title>04-盒子模型</title>
    <style>
        span {
            display: inline-block;
            background-color: #f00;
            width: 50px;
            height: 50px;

            border: 5px solid #0f0;
            padding: 20px;
            margin-right: 40px;
        }
    </style>
</head>
<body>

<span>span</span>666

</body>
</html>